Your Hair.

Let us clarify: Running your fingers through your hair right after swimming is a bad idea. "Your polish is softer when you get out of the water, so it can easily flake off if it gets caught on a strand of hair," says cosmetic chemist Joseph Cincotta. (Throw a wide-tooth comb in your beach bag to use instead.)

Your Suitcase.

Unzip it carefully. Or, even though it sounds crazy, ask someone else to do it for you. "It's one piece of advice I always give my clients, because zipping and unzipping your suitcase snags nails," says manicurist Elle.

The Beach.

Sand is gritty and can dull your polish, especially on toes if you take a nice long walk on the beach. Spiff them up with a layer of topcoat, or try rubbing a shine-enhancing dry oil (like cuticle oil, almond oil, or olive oil) on nails once a day to keep them shiny.